A kind of non-temporal synchronous underwater positioning system and method based on broadcast polls
Technical field
The present invention relates to Underwater Navigation field, and in particular to a kind of based on broadcast polls and non-temporal synchronous Underwater Navigation
System and method.
Background technology
In recent years, with Underwater resources exploitation dynamics increasing and undersea search activity rise, Underwater Navigation gets over
Paid attention to come more people, and due to the high frequency characteristics of electromagnetic wave signal so that it can not carry out effect spread under water, sound wave
Method the most feasible is transmitted as signal during Underwater Navigation.Underwater Navigation is mostly based on ranging, binding site solution
Calculate the relative position for drawing positioning target.In terms of time angle, the underwater positioning system based on ranging is broadly divided into two classes:
1) time synchronized ranging;2) non-temporal synchronous range finding.
In ranging process, generally combined using the underwater spread speed of sound wave and propagate duration to calculate anchor node with determining
Oblique distance between the target of position.Time synchronized refers to need to keep anchor node consistent with the sequential for positioning target in ranging process
Property, so as to calculate the time difference between transmitting positioning signal and receives echo-signal.The realization of existing time synchronized is
It is synchronous come the deadline by stamping timestamp in water sound communication signal based on realizing underwater sound communication, however, current water
Sound communication can not be realized really under water, and due to the complexity of underwater environment, underwater acoustic channel is highly prone to disturb, its
The reliability of communication is very unstable.
Non-temporal synchronous range finding refer to measure anchor node and position target between oblique distance when, it is not necessary to by the two when
Sequence synchronizes, but by way of repeatedly intersecting measurement and making difference, draw anchor node and position the oblique distance between target.Remove
Outside this, in order to shorten locating periodically, in non-temporal synchronous alignment system, generally requiring transponder can be operated in
Multiple frequency ranges, at present the technique of multi-beam transducer can not realize the preferable shape for not producing interference mutually between multiband
Condition, therefore, this also brings uncertain influence to non-temporal synchronous alignment system.
Chinese Patent Application No. CN200910039154 patent of invention discloses a kind of underwater positioning system and method, can
To realize the positioning of submarine target.The limitation of this method, which is embodied in, needs passage time stamp to carry out time synchronized, in the time
Need to carry out information transfer using the underwater sound in synchronous process, and the complexity of underwater acoustic channel can not ensure to realize stabilized communication.
Chinese Patent Application No. CN201410073287 patent of invention discloses a kind of Underwater Navigation navigation system and method.The invention
Need also exist for synchronizing the time of anchor node.In addition, it is also necessary to pseudorandom spread spectrum is carried out, it is this to use multi-frequency
Sound wave carry out the positioning method of underwater sound communication under water, higher requirement is proposed to transducer, the interference being subject to is also more
Seriously.
The content of the invention
Present invention aims at a kind of non-temporal synchronous submarine target location tasks of completion of offer based on broadcast polls
Non-temporal synchronous underwater positioning system and method.
To achieve the above object, following technical scheme is employed:Three anchor nodes are at least needed in system of the present invention
With the Underwater Navigation for carrying a transponder target, each anchor node arrangement is under water and position coordinates is known, anchor section
The transducer of point keeps centre frequency consistent with positioning the transducer of target response device;The transponder of positioning target uses broadcaster
Formula is sent out positioning signal, and carries out the transmission of positioning signal in a manner of poll to each anchor node, and anchor node also leads to
The mode replied successively is crossed to respond;Each anchor node has a time shaft of oneself, the starting point of each anchor node time shaft with
First broadcast polls signal for receiving positioning target response device is starting point, is judged thereafter through the division time cycle current
Whether polling signal is one's own poll positioning signal, and makes corresponding action.
Further, poll positioning signal is 10 pwm signals that frequency is fixed, and is sent when polling cycle starts.
Further, the AD acquisition ports of anchor node only one's own polling signal at hand when just open, respond
AD acquisition ports are closed after end, avoid external interference from having an impact the reliability of underwater positioning system.
Localization method of the present invention, comprises the following steps:
Step 1, electric in alignment system, all anchor nodes, which are in, receives state, and AD acquisition ports are opened, and position the response of target
Device starts outside broadcast polls positioning signal;
Step 2, anchor node receives positioning signal and responded;
Step 3, position target and calculate oblique distance;
Step 4, target location is positioned to resolve.
Further, in the localization method, anchor node number consecutively is A1, A2, A3, and position coordinates is respectively (x1, y1,
z1)、(x2, y2, z2)、(x3, y3, z3);Underwater Navigation target is designated as O (x, y, z);A length of T during locating periodically;Locating periodically embeds
Polling cycle;A length of t during polling cycle;Polling cycle numbering is t1, t2, t3, and anchor section numbering is corresponding with polling cycle;Open AD
The acquisition port time difference is Δ t;
In step 1, the transmission cycle of positioning signal is collectively constituted by two nested cycles, and large period is locating periodically, week
Phase duration T sets itself as needed;Large period is nested with minor cycle, as polling cycle, a length of t during polling cycle, that is, has T
=t*i, polling signal numbering is ti, i=1,2,3, polling cycle numbering and anchor node numbering are corresponding one by one.
Further, in the step 2 of methods described:
2-1, when A1 anchor nodes receive the positioning signal in first t1 polling cycle, open timer and start to count
When, and response signal is sent out, time Δt closes AD acquisition ports, and timer continues timing, waits next t1 polling cycles
The arrival of signal, other anchor nodes keep silent;
2-2, when A2 anchor nodes receive first t1 polling signal, when opening timer, when timing is to t- Δ t
Carve and open AD acquisition ports, prepare to receive the positioning signal of t2 polling cycles, responded after receiving positioning signal, send response
Echo, then closes AD acquisition ports in t+ time Δts, and other anchor nodes keep silent;
2-3, when A3 anchor nodes receive first t1 polling signal, when opening timer, when timing to 2*t- Δs t
When open AD acquisition ports, prepare to receive the positioning signals of t3 polling cycles, responded after receiving positioning signal, send response
Echo, then closes AD acquisition ports in 2*t+ time Δts, and other anchor nodes keep silent.
Further, in step 3, when the transponder that the response signal of A1 anchor nodes is positioned target receives, positioning
Target is designated as t1, will combine the underwater biography of sound wave according to sending positioning signal and receiving the time difference of response echo signal
Speed v is broadcast, calculates positioning target and the oblique distance of A1 anchor nodes
By that analogy, positioning target will obtain the oblique distance with three anchor nodes, respectively D in a locating periodically1、D2、
D3。
Further, in step 4, the positioning target that is obtained according to the position coordinates of known three anchor nodes and measurement
With the oblique distance of three anchor nodes, list position and resolve equation group:
The relative position coordinates O (x, y, z) of positioning target can be calculated according to least square method.
Compared with prior art, the invention has the advantages that:Reasonable in design, convenient and practical, calculating simply, can be completed non-
The submarine target location tasks of time synchronized.
Brief description of the drawings
Fig. 1 is the operating diagram of present system.
Fig. 2 is that the involved three side positions for carrying out position resolving with positioning target according to anchor node solve in a system of the invention
Calculate schematic diagram.
Embodiment
The invention will be further described below in conjunction with the accompanying drawings:
Fig. 1 show the operating diagram of the underwater positioning system based on broadcast polls, by three anchor node A1, A2,
A3, and carry the positioning target composition of transponder.Anchor node arranges that the position coordinates of anchor node is respectively A1 under water
(0,0,0), A2 (9,4,1), A3 (- 3, -5,1).The transponder of positioning target is sent out positioning signal, as needed positioning week
Phase T is 750ms, and polling cycle t is 250ms, Δ t=50ms.Position the transponder of target and changing for each anchor node carrying
Energy device frequency is 35KHz, and positioning signal is 10 35KHz pwm signal.
After system electrification, all anchor nodes, which are in, receives state, and AD acquisition ports are opened.Positioning target transponder start to
Outer broadcast polls positioning signal.
When A1 anchor nodes receive t1 polling signals, opening timer timing, A1 anchor nodes give a response, are sent out ringing
Induction signal, when timer timing to 50ms moment, close AD acquisition ports.
When A2 anchor nodes receive t1 polling signals, timer timing is opened, t1 polling signals are not given a response, closed
AD acquisition ports are closed, until timer timing opens AD acquisition ports, wait t2 polling signals to arrive to the 200ms moment.When A2 anchor sections
When point receives t2 polling signals, response signal is sent out, timer timing to 300ms moment, closes AD acquisition ports.
When A3 anchor nodes receive t1 polling signals, timer timing is opened, t1 polling signals are not given a response, closed
AD acquisition ports are closed, until timer timing opens AD acquisition ports, wait t3 polling signals to arrive to the 450ms moment.When A3 anchor sections
When point receives t3 polling signals, response signal is sent out, timer timing to 550ms moment, closes AD acquisition ports.
When the AD acquisition ports of anchor node are closed, anchor node is in silent status, without task action, until timer
Timing is until locating periodically terminates.
When the transponder that the response signal of A1 anchor nodes is positioned target receives, positioning target is according to transmission positioning signal
Time difference with receiving response signal is 8.18ms, will combine the underwater spread speed 1.5m/s of sound wave, and calculate positioning
Target and the oblique distance D of A1 anchor nodes1=6.14m.
When the transponder that the response signal of A2 anchor nodes is positioned target receives, positioning target is according to transmission positioning signal
Time difference with receiving response signal is 8.87ms, will combine the underwater spread speed 1.5m/s of sound wave, and calculate positioning
Target and the oblique distance D of A2 anchor nodes2=6.65m.
When the transponder that the response signal of A3 anchor nodes is positioned target receives, positioning target is according to transmission positioning signal
Time difference with receiving response signal is 15.178ms, will combine the underwater spread speed 1.5m/s of sound wave, and it is fixed to calculate
Position target and the oblique distance D of A3 anchor nodes3=11.38m.
After each locating periodically terminates, system will return to the position of three time differences and three oblique distances for positioning target
Resolving is put, it is as shown in Figure 2 that position resolves schematic diagram.According to three known anchor node position coordinateses and corresponding oblique distance,
It is listed below resolving equation group:
With reference to least square method, the relative position coordinates for drawing positioning target are (3.6,4.1,2.8).
In the present invention, the answer signal of broadcast polls signal and anchor node is passed in the form of sound wave in underwater acoustic channel
Defeated, the centre frequency for the transducer applied under the frequency and actual scene of its signal matches.It need not lead in position fixing process
Cross the repetition of underwater sound communication or multi-frequency underwater sound signal or cross-reference carrys out deadline synchronization, during the starting of each anchor node
Between since being received first t1 polling signal.
Using the present invention, it is possible to achieve the positioning of equipment such as swim underwater of underwater robot, move under water under water device, underwater sightseeing needs
Ask, the stabilization of underwater positioning system is improved by the current uncertain technology of immature or reliability of use as few as possible
Property and reliability.
Embodiment described above is only that the preferred embodiment of the present invention is described, not to the model of the present invention
Enclose and be defined, on the premise of design spirit of the present invention is not departed from, technical side of the those of ordinary skill in the art to the present invention
The various modifications and improvement that case is made, it all should fall into the protection domain of claims of the present invention determination.